This invention is a filling device for use on machines designed to fill containers using counterpressure.
French Pat. No. 2,075,635 discloses filling means using counterpressure in which the filling and cut-off operations are controlled using a course control switch and an electric sensor.
In this device, as the bottle to be filled is moved into place, it makes contact with the seal gasket of a vertically movable centering hub. As the bottle continues to rise, the hub activates a course control switch. The latter, connected electrically to a solenoid valve, activates the solenoid, which then creates a pressure differential between two opposing surfaces of a vertically sliding sleeve. This causes the sleeve to rise, exposing an annular orifice through which pressurized gas from a filling tank enters the bottle to be filled, thereby pressurizing it. When the bottle is at the same pressure as the filling tank, a second sliding sleeve rises and exposes a second annular orifice through which the liquid to be bottled flows into the bottle.
Through the use of electrical fill control, means of this type make it possible to do without precision-calibrated springs. However, they also require the use of a great many mechanical moving parts, such as springs and sliding sleeves, which come into contact with the gas from the pressurized tank and with the liquid being bottled. Therefore, in the interests of hygiene, such means require that numerous seals be installed and that the delivery mechanism be washed frequently. In addition, given the force required for raising the sliding sleeves, it is necessary to connect the solenoid valve to a gas source with a pressure higher than that which prevails in the supply tank.